Trim the woody ends of the asparagus spears, then cut the spears into 2-inch pieces.
Wipe mushrooms clean of any dirt, and remove stems. Cut caps into chunks (about 4-6 per mushroom head, depending on size).
Peel and finely chop red onion.
Peel and mince garlic cloves.
Heat 1 tablespoon olive oil in a 12-inch nonstick skillet over medium-high heat until shimmering.
Add red onion and sauté until tender and starting to brown, about 3 minutes.
Add mushrooms. Cook until they release their liquid and start to brown, about 10 minutes. Stir frequently, and season with salt and pepper to taste. A few minutes before the mushrooms are done, stir in minced garlic. Remove from pan when mushrooms are golden brown.
Add the remaining tablespoon of olive oil, then add asparagus to pan. Pour in 3 tablespoons water, and cover the pan for 3 minutes.
Remove cover, and sauté until water evaporates and asparagus is bright green and tender, another 3 minutes. Season with salt and pepper to taste.
Add mushroom and onion mixture back into the pan along with 1 teaspoon of thyme leaves. Stir together with asparagus to warm through.
Garnish with additional fresh thyme leaves to serve.
Notes
Storage Tips: Store leftover mushrooms and asparagus in an airtight container in the refrigerator for 3-4 days. Reheat in the microwave or in a skillet on the stove.Expert Tips: Note that your asparagus cooking time will depend on the thickness of the asparagus spears. If you have very thin asparagus spears, you’ll need much less time to cook them and probably can skip the steaming stage.Mincing or grating your garlic is highly recommended, so that you don’t end up biting into a chunk of garlic.Use a large skillet to avoid overcrowding. Adding too many vegetables to a small skillet leads to steamed and soggy vegetables.